Chlamydia in atherosclerosis.

Among the many theories of the pathogenesis of atherosclerosis has been a possible role for infection. However, the possibility that a viral infection initiates or perpetuates damage to the arterial wall has received less attention than other more widely recognized risk factors. Recently, a newly described Chlamydia species, Chlamydia pneumoniae, strain TWAR,' has been associated with atherosclerosis in seroepidemiological studies. The Chlamydiae are classified as bacteria but grow only intracellularly. C. pneumoniae causes pneumonia, bronchitis, pharyngitis, and sinusitis and is transmitted from human to human via the respiratory tract.2 It does not cause sexually transmitted disease (Chlamydia trachomatis) or infect birds and lower mammals (Chlamydia psittaci).